Do your business
What's the meaning of the phrase 'Do your business'?
Euphemism for defecation.
What's the origin of the phrase 'Do your business'?
'Business' is a word that is used in numerous contexts. 'Doing the business' has been used as a euphemism for sexual intercourse since the 17th century. Sir John Harington provides and example of that in his Epigrams, 1612:
[The proctor] doth her [his wife's] busines with great satisfaction.
To 'do (or 'be at') one's business' has an equally long pedigree as a euphemism for defecate. Sir John clearly liked a euphemism as an early example of the second expression is found in his Apology, 1596.
He [Sir Thomas Markham] loues an easie cleanly Iaxe maruellous wel; and if one be his deare friend, he will let him tarrie with him, while he is at his businesse.
[He loves an easy cleanly jaxe marvelous well; and if one be his dear friend, he will let him tarry with him, while he is at his business.]
Harington was well placed as an early user of lavatorial expressions as he is generally regarded as the inventor of the flushing toilet. He published his thoughts on the subject in A New Discourse of a Stale Subject, Called the Metamorphosis of Ajax. Ajax was the name he chose for the new device. This was a pun on the word 'jakes', which was the slang name for a privy (as used in the quotation above, spelled as 'Jaxe'),
Jacksee is still used as a slang term for lavatory, less frequently than fifty years ago, but still quite commonly so in the London area.
See also: The Crapper